Review of volatile organic compound source apportionment by chemical mass balance

The chemical mass balance (CMB) receptor model has apportioned volatile org anic compounds (VOCs) in more than 20 urban areas, mostly in the United Sta tes. These applications differ in terms of the total fraction apportioned, the calculation method, the chemical compounds used in the calculation, the apportionment units, and the source profiles applied. Nevertheless, they s how similar results for VOC fractions contributed by different sources. Gas oline vehicle exhaust, liquid gasoline, and gasoline evaporation contribute up to 50% or more of the ambient VOCs in many of these studies. Relative m otor vehicle source contributions determined by CMB were similar to or larg er than their proportions in emissions inventories. Coatings and solvent co ntributions from CMB were much lower than the proportions attributed to the se sources in current emissions inventories. Several measurement and report ing conventions would facilitate CMB analyses of VOC data sets. (C) 2001 El sevier Science Ltd. All rights reserved.